Oxy acetylene cutting is known by many names, such as oxy cutting, oxy-fuel cutting, gas cutting or flame cutting. It is a thermal process that uses a combination of fuel gases and pure oxygen to cut metal.
Flame cutting relies on pre-heating. First, the flame is used to heat up a localised spot on the metal. Then a high-pressure stream of pure oxygen is directed towards this area. This oxygen stream triggers a rapid chemical reaction, effectively “burning” through the material.
With cutting temperatures reaching up to 3500°C, the torch is designed with a specialised nozzle: outer ports deliver the pre-heating gases, while a central jet delivers the high-pressure oxygen that performs the final cut.
Flame cutting is excellent for cutting carbon steel due to the specific chemical reactions involved. As the metal reacts with the oxygen, it forms iron oxide, which has a lower melting point than the steel itself, allowing for a clean, continuous cut.
Therefore, it is a good option when working with ferrous metals, but is pretty much unusable with aluminium or even stainless steel. Aluminium oxide has a higher melting temperature than the base metal, creating a “skin” that prevents a clean cut. Stainless steel, on the other hand, is designed specifically to resist oxidation, lacking the reactive properties necessary for flame cutting to be effective.
For thick plates made from materials other than carbon steel, alternative methods like waterjet cutting are recommended to achieve high-quality results.